The
Middle East appears on the brink of wider sectarian war engulfing Iraq
and Syria with radical Islamist insurgents wantonly kidnapping,
torturing and killing civilians and security forces, UN human rights
investigators said today.

Secretary General Ban Ki-moon said he is deeply concerned about Iraq's
rapidly deteriorating stability, including reports of mass summary
executions.

Those atrocities and terrorist attacks
are taking place as the Islamic State of Iraq and the Levant, or ISIS,
an Al Qaeda-inspired Sunni Muslim militant group, looks to link areas
under its control on both sides of the Iraq-Syria border.

It came as video emerged reportedly
showing ISIS militants carrying out the systematic execution of dozens
of prisoners in Syria.

Taking no prisoners: Footage posted on YouTube appears to show ISIS militants carrying out summary executions on dozens of captured soldiers in Syria

The U.N. said forces allied
with ISIL had almost certainly committed war crimes by executing
hundreds of non-combatant men in Iraq over the past five days.

ISIS
seeks a caliphate ruled on medieval Sunni Muslim precepts in Iraq and
Syria, fighting against both Iraq's Maliki and Syria's Bashar al-Assad.

It
considers Shiites heretics as deserving of death and has boasted of
massacring hundreds of Iraqi troops who surrendered to it last week.

'There
is a real risk of further sectarian violence on a massive scale, within
Iraq and beyond its borders,' Ban told reporters.

He
said all Iraqi leaders - political, military, religious and community -
must 'ensure that their followers avoid acts of reprisal' and together
head off more conflict.

On brink of sectarian war: The UN said atrocities are taking place as ISIS looks to link areas under its control on both sides of the Iraq-Syria border

He said he has been urging Prime Minister Nouri al-Maliki's Shiite-led government to take a more inclusive approach.

'The
Iraqi government should have one state. Whether it is Sunni, Shiite or
Kurds, they should be able to harmoniously live together,' Ban said.

'I
hope that with the strong support of regional countries and the
international community in a broader sense, we will be able to help the
Iraq government first of all to restore peace and stability in their
country.'

Ban said governments that allow human right rights abuses become 'breeding grounds for extremism and terrorism.'

Interntional condemnation heightened today as the UN published a report on the situation.

Vitit Muntarbhorn, an international law expert who took part in the inquiry, said: 'We predicted a long time ago the dangers of spillover both ways, which is now becoming a regional spillover. We are possibly on the cusp of a regional war and that is something we're very concerned about.'

UN human rights chief Navi Pillay said on Monday forces allied with ISIS in northern Iraq had almost certainly committed war crimes by executing hundreds of non-combatant men over the past five days.

Sectarian violence: The executions in Syria resemble those in Iraq, above, which the UN has warned could contribute to an all-out regional war

Brutal: UN Secretary General Ban Ki-moon urged all sections of Iraqi society to work together to prevent disaster

A report presented on Tuesday to the UN Human Rights Council said foreign Sunni jihadi militants and funds had poured into Syria where rebel factions including ISIS were wantonly abusing civilians in zones they controlled.

'A regional war in the Middle East draws ever closer. Events in neighbouring Iraq will have violent repercussions for Syria,' the investigators' report said.

'Growing numbers of radical fighters are targeting not only Sunni (Muslim) communities under their control but also minority communities including the Shi'ites, Alawites, Christians, Armenians, Druze and Kurds,' it said of Syria.

Its reference to Sunni militants targeting Sunni civilians involved forceful pressure on Sunni women to comply with sharia (Islamic religious law) and acts of revenge against Sunnis who had served in the Syrian government.